Air powered stapling machine



June 27, 1961 w. A. FoRREsTER 2,989,948

AIR POWERED STAPLING MACHINE June 27, 1961 W. A. FORRE'STER AIR POWEREDSTAPLING MACHINE 4 Sheets-Sheet 2 Filed July 7, 1954 June 27, 1961 w. A.FoRREsTER 2,989,948

AIR POWERED STAPLING MACHINE Filed July 7, 1954 4 Sheets-Sheet 3 June27, 1961 Filed July 7, 1954 l l i?. m5 w) 7;0 d77 101 im. /g In. `I l118 l 19 1 12,2 ,07 m3 78 l W02 .5. 77 I 75 19 l Il i l I i,

4 Sheets-Sheet 4 United States Patent O 2,989,948 AIR POWERED STAPLINGMACHINE William A. Forrester, Herrin, lll., assguor to InternationalStaple and Machine Company, Herrin, Ill., a corporation of PennsylvaniaFiled July 7, 1954, Ser. No. 441,773 30 Claims. (Cl. 121-21) Thisinvention relates to uid operated motors, and in particular is concernedwith a stapling machine having an air powered, single cycle motor. Thesingle cycle motor is adapted to be actuated -by a trigger whichinitiates the cycle and is thereafter rendered inoperative by meansassociated with the air motor so that continued depression of thetrigger does not produce a repeating of the motor operation.

The air powered motor which is used in this stapling machine has beenparticularly provided with power operating means whereby it is enabledto operate a piston in a reciprocable manner. The piston drives a stapledriving blade and retractible anvil in a retractible anvil type ofstapling machine such as that disclosed in the Schafroth Patent No.2,469,054, assigned to International Staple and Machine Company. Thesemachines are designed to operate from a reciprocable driving forceIwhich drives the staple driving blade and coordinately also drives theretractible anvils. The retractible anvils are caused to rotate about apivot point by suitable linkages in such a manner that when the staplesare driven thereagainst they are clinched to hold together the materialbeing stapled.

By means of this invention, there has been provided an air powered motorwhich is adapted to be used in a retractible anvil stapling machine ofthe type described or any stapling machine which utilizes a reciprocabledriving and actuating force. A signal feature of this invention residesin the association of the trigger mechanism Iwith the air powered motorand the oper-ating means for the driving blade such that an entire cycleof operation may be completed by merely depressing the trigger. Thus,the trigger need not be -released to complete the staple drivingoperation and retraction and only one initiating or triggering operationis required. It is always possible that the operator may ybe negligentor careless in an operation requiring more than one manipulation of amachine, so there is no possibility of faulty operation due to thesingle actuation required in this device. Another feature of 4theinvention is a Valving arrangement that forces the air motor piston to aretracted position and maintains it there, except when there isintentional operation of the valve mechanism.

There has further been provided in this invention means for adjustingthe degree of penetration of the retractible anvil into the material tobe stapled together. This has been accomplished by providing anadjustment screw which elevates the staple driving works with respect tothe base of `the machine which rests upon the workpiece. This adjustmentincludes a threaded penetration control screw which may be adjustedwithout interfering with the operation of the air powered motor in anyway and presents an easily accessible penetration control mechanism.

Accordingly, it is an object of this invention to provide a uid operatedmotor having a single cycle which may be initiated by a depression of atrigger to drive an operating member, and wherein the completion of thecycle and retraction is effected by the movement of the driven member.

It is a further object of this invention to provide an air powered motorfor a stapling machine having a single cycle, and wherein the depressionof a trigger completes the external -force required to effectuate thefull single cycle operation.

Mice

It is still another object of this invention to provide an air poweredmotor having a main valve and a poppet valve for use with a staplingmachine wherein the actuation of the main valve is effected by a triggerto drive an operating member, and wherein the stapling operation iscompleted by the movement of the operating member so as to return themain valve to its original position in dependent of the release ofthetrigger.

Yet a further object of this invention is to provide an air poweredmotor having a single cycle for use with a stapling machine in which thedriving force is eit'ected through the opera-tion of a driving piston insuch a manner that at the end of the driving cycle there is a reductionof power applied by the piston to prevent too great a driving forcebeing furnished to the staple. This reduction of power at the end of thedriving operation greatly reduces the possibility of breakage in thestaple clinching operation.

Another object of this invention is to provide anair powered motorhaving a trigger and associated cam mechanism for initiating the actionof the motor and means on the cam for completing the cycle of the motorindependent of any further actuation or release of the trigger.

A further object of this invention is to provide a retractible lanvilstapling machine having a penetration control mechanism wherein theextent of penetration of the retractible anvils into the material beingstapled can be varied by a control screw.

Still another object of this invention is to provide a retractable anvilstapling machine powered by a uid motor having a penetration controldevice adapted to vary the penetration of the anvils into the materialbeing worked upon in such a manner that a control screw can be adjustedto vary the starting elevation of the anvils without effecting thelength of stroke of an operating member actuated by said motor.

Yet a further object of this invention is to provide a single cyclemotor actuated by a single 'applied control force in which there ismeans for varying the length of stroke of an operated piston.

Still another object of this invention is to provide a retractibleanvile stapling machine having a pneumatic motor wherein the penetrationof the retractible anvils may be varied by a control screw which variesthe elevation of the motor and its operating member and the retractibleanvils associated therewith.

Still another object of this invention is to provide an air poweredretractible anvil stapling machine which can be completely operated toeffect the entire stapling opertion Iby a single depression of thetrigger in such a manner that it may be operated by unskilled workmenwith no opportunity for jamming.

Further objects of this invention will appear in the detaileddescription which follows and will be further apparent to those skilledin the art.

For the purpose of illustration, two forms of air powered motors aredisclosed in a schematic manner. Both of these vmotors are adapted to beused with stapling machines and a preferred embodiment is shown with acomplete stapling machine for the purpose of description. It is to beunderstood that these drawings are for the purpose of illustration ofthis invention and that the invention is not limited thereto.

In the drawings:

FIG. 1 is a view in side elevation of the stapling machine;

F-IG. 2 is a view in front elevation of the machine;

FIG. 3 is a sectional view in elevation taken along the axis of themachine;

FIG. 4 is an enlarged view in section showing the main valve of FIG. 3;

FIG. 5 is a plan view in section taken on the line 5-5 of FIG. 2;

FIG. 6 is an enlarged view in plan section showing the poppet valve;

FIG. 7 is a plan view of the valve casting;

FIG. -8 is a sectional view taken on the line 8--8 of FIG. 7 showing themain Valve -and port arrangement;

FIG. 9 is a fragmentary view in vertical section showing the portarrangement to the piston cylinder;

FIG. 10 is a view in section taken on the -line 10--10 of FIG. 7 showingthe poppet valveA housing;

FIG. 11 is a view in section taken on the line 11-11 of FIG. l showingthe main valve port arrangement;

FIG. -12 is a schematic View showing a slightly modified air motor;

FIG. 13 is a schematic view showing a further modication of the airmotor;

FIG. 14 is a pictorial view of the trigger;

FIG. l5 is a sectional view of the stapling machine taken on line 15-15of FIG. l.

Reference will now be had to FIGS. 1, 2 and 3 wherein the staplingmachine of this invention is generally indicated at 20. The machineincludes las its main elements a base 21, a handle 22, and an air motor23. Also, a trigger mechanism 24 and penetration control assembly 25 areshown in FIGS. l, 2 and 3.

The hase 21 is illustrated as a casting, having two generally L-shapedside pieces 26 which are connected together at the bottom by braces 27.This arrangement provides an elongated, channel-shaped base, within theinterior of which channel is positioned a conventional staple feedingmechanism generally indicated at 28 which, per se, forms no part of thisinvention. The L-shaped base members 26 provide uprights 30 that, asshown especially in FIG. l5, spread laterally and forwardly, as well asupwardly, from the horizontal base elements. On their forward -faces thetwo side elements 30 of the base receive two guide strips 31 that aresecured to the Side elements 30 by screws 33. The guide strips presentinwardly turned edges that constitute tracks for a vertically movablestaple driving assembly to be described.

A penetration control bar 34, for a purpose to appear, extends acrossthe yforward faces of the two uprights 30. It is secured at its ends byscrews 35 that pass through the guide strips 31 and into the uprights30. A magazine retaining rod 36 (lower right of FIG. 3) extends betweenthe side pieces 26 to overlie the forward end of a cartridge of staplesand guide the same adjacent the driving blade.

A motor supporting frame or chassis 40 fits between the guides 31 on theuprights 30 of the base. Viewed from the front (see FIG. 2, wherein itso appears but must not be confused with the track strips 31. CompareFIG. 15), it is in the shape of an open rectangle, and its sides areprovided with grooves 41 to engage the track strips 3.1 and to beretained by them. The grooves and strips enable the chassis 40 to beadjusted vertically on the strips. The chassis 40 is also provided withslots 42 in it vertical side portions, to receive the control bar 34 andpermit the chassis to move vertically over the control bar. As willappear, the chassis 40 supports the air motor 23 and the handle 22, sothat when it is adjusted upwardly and downwardly the air motor and alsothe handle 22 move with it.

The bottom wall of the chassis 40 has a threaded opening 43 within whicha penetration control screw 44 is received. This penetration controlscrew 44 is provided with a knurled upper ange 45 and a bottom ange 46spaced .therefrom a distance equal to -the width of the penetrationcontrol bar, which ts therebetween, as shown in FIGS. 2 and 3. A knurledand threaded lock nut 47 is provided to fit against the bottom wall ofthe chassis to lock the penetration control screw in position.

The air motor, as best shown in FIGS. l, 2, and particularly FIG. 3, isformed from an aluminum casting 50 mounted on the chassis 40 (andforming a lower cylinder head and a valve-receiving member), a cylinder51, an upper cylinder head 52, and the handle 22. Screws 521 havingtheir heads above the upper cylinder head 52, and passing downwardlythrough the lower cylinder head 50, are threaded into the chassis 4%(the front screws) and the handle 22 (the rear screws) to secure theseparts together.

The cylinder contains a piston 53 connected to a piston rod 54 extendingthrough a central opening in the casting 50. The piston rod is connectedat its lower end to a drive block 55. A spring 56 is situated within anupper recess 57 in the valve casting so as to contact the bottom of thepiston 53 when it approaches its lowermost position in the cylinder.

The actual stapling mechanism of the machine includes a flanged driveblade `64I connected to the bottom of the drive block 55 through bladespacing shims 59. These shims control the tightness of the staple clinchthrough the relative positioning of the bottom of the blade with respectto'the retractible anvils at the limit of the downward operation of themechanism, as will appear. 'l'he blade is adapted to contact the head ofa staple, as shown in FIG. 3. The retractible anvil mechanism andlinkage of the machine are portrayed in FIGS. 2 and 3 where it is seenthat two links 62 are connected at their tops by pivots 621 to theforward Aface of the drive block 55 and are connected at their bottom bypivots 622 to rotatable anvils 63. The anvils 63 are adapted to bepivoted about pins 64 which are supported in the lower part of thechassis or frame 40. 'Ihese anvils have anvil portions 65 projectingfrom their back faces, and which when extended, directly underlie thedriving blade so that in the stapling operation a staple is driven bythe blade against the anvil arms and clinched in a manner such as thatdisclosed in the Schafroth Patent No. 2,469,054, or otherwise as isconventional in this art.

A stroke control screw 69, shown in FIG. 3, is provided at the bottom ofthe drive block 55. This screw is adjustable and forms the part of thedrive block that contacts a dog 142 on the cam 131 of the trigger, aswill be later described.

The air motor 23 has as its main control elements a main valve 70 havinga vertical axis and a poppet valve 71 having a horizontal axis, as isbest shown in FIGS. 3 and 5, respectively. In order to control theoperation of the main valve, and through it the air motor, a triggermechanism 24, as shown in FIG. 3, is provided, which will be more fullydescribed hereinbelow. All of these control elements are situated withinand supported by the handle 22, the valve casting 50, and the cylinder51 as a complete unit which is secured to the chassis 40 and is adaptedto move with it relatively to the base 21.

Within th'e handle 22, shown in FIG. 3, is an inlet 72 which is adaptedto be secured to a source of high pressure air of the order of 50 p.s.i.This inlet communicates with an inlet high pressure chamber 73, shown inFIG. 4, which includes a valve seat 74 formed at the bottom of the valvecasting 50. A passage 75 leads from valve seat 74 to an opposing valveseat 76. On the other side of the valve seat 76 is an exhaust chamber 77which is in communication with passage 78 that finally registers withtwo exhaust ports 79 that open to below the valve casting 50.

Another passage 82 leads from the passageway 75 into the bottom of thecylinder 51 beneath the piston 53, as best shown in FIG. ll.

The main valve 70 is of the twin valve type having an upper valve 83 anda lower valve 84 connected together by a valve rod 85, as best shown inFIG. 4. This valve has at its bottom an operating rod 86 which isadapted to be operated by the trigger mechanism. Proper sealing iseffected by means of an O-ring 90 which seals the inlet chamber 73against leakage to the outside past the operating rod 86.

A threaded cap 87 closes the top of the exhaust chamber 77 and has acentral bore 88 to receive a valve guide pin 89. This provides forproper centering of the valve 70 when it is reciprocated in itsoperation. A valve spring 92 is seated within an annular recess 93 ofthe cap and bears against the upper side of valve 83 to maintain thevalve in a normally unoperated position, shown in FIG. 4. In thisposition, the valve 83 is closed to exhaust against valve seat 76 andthe valve 84 is opened to pressure with respect to the valve seat 74 sothat the pressure port 82 conducts high pressure air from the inlet 72to the bottom of the cylinder. It is evident that the two elements ofthe valve 70 can connect the bottom of the cylinder, by passage 82,alternately to pressure, when the valve 84 is open, or to exhaust whenthe valve 83 is open.

yThe secondary valve 71 has a similar operation with respect to the topof the cylinder. Its communicating ports are best shown in FIGS. 5, 6,7, 10 and 1l. A pressure port 98, shown in FIG. ll, in the handle member22 leads from pressure chamber 73 to a registering opening 100 in thevalve casting 50 that opens into a poppet valve chamber 101 so that highpressure air is always in communication with some portion of thischamber. This chamber is closed at one end by an O-ring seal 102 whichis prevented from popping out by a spring ring v103. The other end ofthe chamber 101 includes a valve seat 104 on the other side of which isa passage 105 leading to a valve seat 106.

At the other end of the valve casting 50 there is a poppet valve chamber107 into which a portion of the exhaust passage 78 connects, so that thechamber 107 is always open to the exhaust ports 79. Situated medially ofthe valve 71 and communicating with the passage 105 is a port Y111Iwhich passes up through a tube 112, shown in FIG. 9, exteriorly of thecylinder 5d, and continues through the upper cylinder head to the top ofthe piston 53. The upper and lower cylinder heads have lateral bossesbetween which the tube 112 is clamped.

In order to provide for communication of the outer part of the valvechamber 101 with the under side of the piston at the bottom of thecylinder, for a reason which will appear, the casting is provided with aport 113, as shown in FIGS. 7 and l0, which leads from the valve chamber101 adjacent the sealing ring 102 to the cylinder 51 at bottom of thecylinder 51.

The valve 71, like the main valve 70, is also of the twin valvethree-way type and has two valve members 115 and 116 cooperating withthe valve seats 104 and 106, respectively. A valve rod 117 joins the twovalves and is of a smaller diameter than passage 105 in order to providefor communication and passage of air therethrough. T'he valve member 115of the poppet valve 71 is connected at its top to a valve piston 118which is provided with an -ring seal 119 so as to divide the Valvechamber 101 into two compartments, the top part of which, in FIGS. 5, 6and 7, constitutes a pressure chamber for operation of the valve pistonf1-18.

The other end of the valve 71 has a spring 121 bearing against theexterior of valve member 116 at one end, and against a plate 122 at itsother end. The plate 122 is held in the valve chamber 107 by a springring retainer 123. The spring 121 is -a compression spring and biasesthe valve 71 upwardly in opposition to the position shown in FIGS. 5 and6. The position shown, however, is the normal position when the mainvalve 70 is in the unoperated position of FIG. 3.

It may be seen that the upper end of the cylinder 51 is alternatelyconnected to pressure or exhaust by the valve 71. When that valve is asshown in FIGS. 5 and 6 the `top of the cylinder is exhausted, becausethe passage 1-11 is connected around the valve 116 to the exhausts 79;and, at the same time, the high pressure is cut off from the top of thecylinder. This condition continues so long as the pressure in the bottomof the cylinder 51 is high enough to act on the valve piston 118, viathe passage 113, and force the valve down against the spring 121. 'Uponrelief of pressure in the bottom of the cylinder, and in the valvepressure chamber, the spring 121 forces the valve 71 up in FIGS. 5 and6, to close oi the exhaust and to admit high pressure to the top of thecylinder 51.

The trigger mechanism 24 which is used with the air motor isparticularly shown in FIGS. 3 and 14. This trigger mechanism has as itscomponent parts a trigger and a cam 13i1. 'Ihe trigger 130 has opposedside pieces 132 disposed in vertical relationship and connected togetherby a horizontal brace 133. The side pieces are pivoted about a pin 134which is fitted within bifurcated portions 135 depending from the handle22. A coil spring having two arms 136 and 137 is mounted around the pin134 in such a manner that the arm 136 bears against the lower portion ofthe handle 2l2, and the arm 137 bears against the brace 133 to urge thespring to the unoperated position shown in FIG. 3.

The cam 131 is pivoted about a cam pin 140 connected between the triggerside pieces l132 so that the cam is in pivotable relation with respectto the trigger. The cam is biased in a counterclockwise manner (as theparts appear inFIG. 3) with respect to the trigger by a spring 141 whichis connected at its lower end to a stud on the brace 133. The cam 131 isheld in the biased position shown in FIG. 3 so that it bears against.the pin 134 in contacting relationship therewith through a dog 142.

The cam 131, besides being provided with dog 142, has an upper camsurface 143 which is contiguous with a vertical scar surface 144. Thepositional relationship is such that in the normal unoperated positionthe cam surface 143 is immediately below the valve operating member 86.

A diagrammatic illustration of the foregoing -air motor which 'may beused with the stapling machine 20, slightly modified for clarity ofillustration, is shown in FIG. 12 and is generally indicated at 150.This air motor includes a valve casing 151 connected to the bottom of acylinder 152 closed at the top by a cylinder head 153. Situated withinthe cylinder is a piston 154 connected to a piston operating rod 155.

The valve casing 151 includes a high pressure inlet 156 opening into ahigh pressure valve chamber 157. This valve chamber is in communicationthrough a passage 158 with a poppet valve chamber 159.

A valve seat 161 is adapted to connect the valve chamber 157 with apassage 162 which is in communication through port 163 with .thecylinder 152 at the bottom side of the piston 154. The other end of thepassage 162 is in communication with the Valve seat 164 opening into anexhaust chamber 165. The exhaust chamber 165 is connected to an exhaustport 166.

A main valve has valve members 171 and 172 connected together by a valverod in such a manner that the valves cooperate, respectively, with valveseats 161 and 164. This valve is biased to the position shown in FIG. 12by a spring 173 bearing at one end against a valve member v164 and atits other end against a piston cap 174. The lower end of the valve 170has an operating rod which will be more fully described hereinbelow.

A poppet valve 1-80 is shown at the right hand side of FIG. l2 and is ofthe twin Valve piston operated type. The poppet valve chamber 159 isprovided with a bore 181 for receiving the piston of the poppet valveand has an upper opening 182 in communication with the cylinder 152 atthe bottom side of Ithe piston. A bleed port 183 is in communicationwith the bottom of the opening 182.

At the lower side of the poppet valve passage 159 is a valve seat 184forming one end of a passage 185 which has at its other end a secondvalve seat 186. A port I187 medially connects the passage 185 with thecylinder 152 at the top side of the piston.

'I'he poppet valve 180 has its twin valve members 190 and 191 adapted tocooperate with valve seats 184 and 186, respectively, through a valverod which connects these valve members and extends upwardly of the valvemember 184 to be iixedly connected to a piston 192. 'I'he valve seat 186communicates with an exhaust chamber 193 (open to atmosphere) withinwhich is supported a poppet valve spring 194 secured at its bottom endby a washer within the chamber.

Returning to the main valve 170 of the modiication in FIG. 12, it willbe seen that the operating member 175 is provided with a detent groove195. An operating handle l196 has detent balls 197 which are biasedagainst the groove 195 by springs 198 so as to hold the handle 196 inthe axial position with respect to the operating member 175, as shown inFIG. 12. However, a force may be applied to cause the balls 197 to rideout of the groove and change the axial relationship of the handlel withrespect to the operating rod.

' It is quite -apparent that the connections and operations of the mainvalve 170 and the poppet valve 180 correspond to the connections andoperations of the valves 70 and 7.1 previously described. The main valve170 is operated by the detented handle 196 and the cap 174 instead of bythe trigger arrangement, as wil-l appear.

In FIG. 13 is shown another modification of an air motor generallyindicated at 200 wherein a valve housing 201 is situated exteriorly as aseparate unit from a cylinder 202. The cylinder 202 contains aconventional piston '203 and piston rod 204 that may be used foractuating a crosshead and associated stapling parts, such as illustratedin FIGS. 1-11.

The valve housing 201 contains a high pressure inlet 205 whichconstantly communicates with a poppet valve chamber 206 and -a mainvalve chamber 207. EIn this modification the poppet valve is indicatedgenerally at 208, and the main valve is indicated at 209. In the valvechamber 207 there is a lower valve seat 211 which leads into a valvepassage 21i2. This valve passage 212 is in communication through a port213 with the cylinder at the lower side of the piston. The valve passage212 is also in communication through a port 214 with a poppet valvepiston chamber 215. At the other end of the valve passage 2.12 is avalve seat 216 which is in communication with an exhaust chamber 217 andexhaust port '218.

The poppet valve chamber 206 previously described is provided with avalve seat 220 spaced from another poppet valve seat 221 by anintermediate valve passage 222 which is in communication with the top ofthe cylinder by a passage 2,23.

The main valve 209 is of the twin valve three-way type having an uppervalve vmember 230 and a lower valve member 231 connected by an operatingrod 232 which extends slidably through the valve housing to a solenoidcoil 233. Biasing the valve 209 in such a manner that the valve 230 isnormally closed against the valve seat 216, is a spring 234. The lowerend of the valve 207 may be slidably sealed in the valve chamber withatmospheric pressure on the lower side. The poppet valve 208 is also ofthe twin valve threeway type having an upper Valve member 240 and alower valve member 241 which is connected to a piston 242. This valve isprovided with a valve spring 243 for biasing the poppet valve toward areverse position to that shown in FIG. 13 when the main valve isoperated.

The soft iron core of the solenoid includes the detent support 245having spring-urged detent balls 246 engageable in a groove around thevalve rod 232. Movement of the core by energization of the coil 233lifts the detent balls and the valve rod when the balls are in thegroove. The operating rod is provided with =a ange 247 upon which avalve return arm 24S may engage. One end of the arm 248 is pivoted tothe supporting frame of the solenoid and the other end projectstoward-the cylinder to be contacted by an adjustable contact nut 249situated Operation It may be convenient to describe the operation of themachine by first referring to the diagrammatic showing o-f FIG. l2.

In the modified motor shown in FIG. l2, the air motor 150, like themotor 23, is adapted to be used with the identical stapling machine 20or in conventional stapling machines having a fixed anvil as well as inother applications.

In the air motor 150, the main valve is maintained in the normallyunoperated position shown, by the force of spring 173. This spring keepsthe valve member 171 closed against its valve seat 164 and the valvemember 172 open with respect to its valve seat 161. In this condition,high pressure air enters through inlet 156 and passes through thepassageway 162 and the port 163 to the bottom of the cylinder below thepiston. Simultaneously therewith, high pressure air is admitted to thetop ofthe valve piston 192 in the chamber 182. The similarity of this tothe principal drawings should be evident, and will be clear from thedetailed description thereof, later given.

High pressure air above the piston 192 causes the poppet Valve to bemaintained in the position shown in FIG. 12 such that the valve member190- is closed against its valve seat 134, and the valve 191 is openedwith respect to its valve seat 186. This connects the top of thecylinder to exhaust by the passages 187, 185, and 193. Accordingly,since the high pressure air ows to the bottom of the piston cylinder 152and the top of the piston is open through the passage 187 to exhaustthrough the valve 191, the piston is kept in the raised position.

The motor is adapted to be operated by pushing upwardly on the operatinghandle 196 so that the valve 172 closes the flow of high pressure airthrough port 163 to the bottom of the piston. As this occurs, the valvemember 171 is opened and the port 163 is thereby connected into theexhaust `chamber 165 and the exhaust port 166. As the pressure beneaththe piston is reduced (also reducing pressure -above the valve piston192), high pressure air passes through the conduit 158 to the piston 192about its annular area through a loose fit with the bore 181. Thisapplied force, together with the biasing action of the spring 194, popsthe poppet valve up to open the valve member and close the valve member191. Therefore, the high pressure air in the passage 158 passes throughthe valve member 190 and the passage 185, and upwardly through thepassage 187 to the top of the piston 154.

Under this applied force at the top of the piston, the piston and pistonrod will move downwardly until the bottom of the piston contacts the topof the piston cap 174, As this occurs, the piston cap moves downwardlyalso a limited amount until it pushes against the top of the valve rod175. As the valve rod 175 is pushed downwardly, it will ride out ofengagement with the detent balls 197 which are urged against theirbiasing springs 198 in such a manner that the groove 195 permits axialdisplacement. Thus, even if the operating handle is held up, the mainvalve and poppet valve will return to the original position shown inFIG. 12 to complete the cycle and return the piston 154 to .the'upwardposition.

After this has occurred, the operating handle 196 must be returned tothe position shown in FIG. 12 to ready it for a new cycle and another`operation of the air motor. Thus, there has been provided in this motora complete single cycle operation lwhich provides a safety featureagainst continued cycling, `and does not depend upon release of thehandle or trigger element to stop the motor.

The foregoing explanation of FIG. 12 gives the general operation of themotor, wherein the main valve initiates the reversals, and the secondaryvalve responds to cylinder-bottom pressure conditions. The operation ofthe principal drawings will now be described.

The stapling machine in its unoperated position, shown in FIGS. 3, 4, 5,6 and 7, has its piston maintained in the elevated position by acombination of actions. Thus, the main valve 70 is kept in the positionshown in FIG. 3 by the force of spring 92 and by static air pressurewhich closes valve 83 against valve seat 76 and opens valve 84 to valveseat 74. The poppet valve 71 in FIGS. 5 and 6 is maintained in -itsposition by the application of air pressure rather than spring pressure.

To explain more fully, high pressure air enters the handle 22 (as from aflexible hose connected to a source of high pressure air) through theinlet 72, and then passes through the valve 84, shown in FIGS. 3 and 4,into the passage 75 and through the port 82, shown in FIGS. 8 and ll, tothe bottom of the cylinder. This establishes a region of high pressurein the bottom of the cylinder. At this time the poppet valve 71 is inthe position of FIGS. 5 and 6, because cylinder-bottom pressure acts bythe passage 113 into the pressure chamber of the valve piston 118 todrive the valve against the force of the spring 121. The top of thecylinder is in communication (FIGS. 5, 6 and 9), by the port 111,through the passage 105, the valve seat 106, the valve chamber 107, andthe passage 7S, with the exhaust passage 79. Hence because of highpressure below it and exhaust pressure above it, the piston ismaintained in this raised position. The poppet valve 71 is kept in theposition shown in FIG. 5, so long as the high pressure remains in thebottom of the cylinder 51, or, in other words, until the main valve 70is shifted to its upper position. It will be noted that the lower sideof the piston 118 is also under a high pressure condition through port100 and passage 98 which lead to chamber 73 which is under the same highpressure as that at the bottom of the cylinder, but since there is arestricted annular area on the lower side of the piston as contrastedwith the upper side, this force and the spring 121 are overriden by highpressure acting on the entire outer surface of the piston 118. Thus, thevalve 115 is urged against valve seat 104, and conversely the valve 116is kept open with respect to its valve seat 106.

The stapling machine can be operated by actuating the trigger mechanism24 by placing a finger under the brace or transverse part 133 androcking the trigger 130 in a clockwise manner about the pivot 134. Whenthis is effected, the cam surfaced 143 of the cam 131 rides under thebottom of the main valve operating member 86, and elevates the valve 70to close the valve 84 and open the valve 83. It will be noted that thecam member cannot give or further rotate counterclockwise about itspivot since the dog 142 contacts the underside of the pin 134; and itcannot rotate clockwise since the cam pivot 140 is to the right (in FIG.3) of the valve rod 86, and thus there is a iirm (though sliding)contact with the bottom of the operating member. The spring 141 aids inholding the cam 131 against clockwise movement about its pivot 140.

As the main valve 70 moves upwardly, it closes its valve member 84against the valve seat 74 and thus cuts ott high pressure through theport 82 to the bottom of the cylinder and piston. As this occurs,simultaneously the valve member 83 is opened away from its valve seat 76so that the port 82 is opened to exhaust chamber 77 and therethrough tothe passage 78 and the exhaust ports 79, which establishes a region oflow pressure or exhaust beneath the piston. This region of low pressureis then simultaneously established through the port 113 to the exteriorof the poppet valve piston 118.

Under this situation, the lower side of the piston 118 of the poppetvalve 71 in the annular area is under high pressure through the passage100 communicating with the high pressure chamber 73, and this causes thepoppet valve 71, under the combined action of the differential airpressure and spring 121, to reverse the valve posi- 10 tion. Thus, thevalve member 115 is opened from its valve seat 104 and the valve member116 is closed against the valve seat 106. Therefore, high pressure canpass from the passage 100 through the inside of the valve chamber 101,through the passage 105 and the passage 111, to the top of the pistonthrough the cylinder head. The reversal of the pressure condition uponthe piston, whereby a high pressure is established at the top of thepiston, thus causes the piston to move downwardly with great force andto effectuate the stapling operation.

When the piston 53 is caused to move downwardly, the piston rod 54 isdriven thereby. After accelerating to a substantial speed, the pistondrives the driving blade against a staple, to hammer the staple'legsdownwardly through the material being stapled. At the same time, thedescending driving block or crosshead 55 lowers the pins 621 at the topof the links 62, thereby spreading the pivots 622 that join the links 62with the tops of the anvil arms 63. This drives the pointed anvils 65through the material in an arcuate manner in the direction of theindicated arrows. This causes a penetration of the rotary anvils intothe material being stapled so that the staple is driven thereagainst andclinched in the usual manner in this type of stapling action.

As the piston is driven downwardly, it comes to a point where just priorto the end of its downward movement it contacts the upper end of thespring 56. This cushions the applied force to the driving blade 60 andthe links 62. This cushioning prevents overclinching and breaking ofstaples and anvils through too great an application of power, and is asafety feature of this invention.

Also, as the piston 53 is lowered, the control screw 69 which isattached to the bottom of the driving block 55, as shown in FIG. 3, willcontact the dog 142 of the cam. This contact causes the cam to rotate ina clockwise fashion about its pivot pin against the biasing action ofthe spring 141 in such a manner that the cam surface 143 rides oli thebottom of the valve operating member 86. When this occurs, the valve isno longer upwardly opposed against the force of the return spring 92,and, accordingly, the valve is returned to the position shown in FIG. 3,This reestablishes the region of high pressure through valve 84 intoport 82 to the bottom of the piston, which returns the poppet valve 71to the illustrated position. The return of the two valves 70 and 71causes a return of the piston to the upward position to complete thestapling cycle. The return of the piston and its piston rod 54 similarlywithdraws the driving blade 60 and the links which operate the rotaryanvils.

It will be noted that at the end of this operation, after the piston hasreturned to its original position, if the trigger is still held inoperated position, the cam 131 is prevented from returning to theposition shown in FIG. 3 by the contacting of the vertical sear surface144 with the side of the valve operating member adjacent its end.

55 This prevents a new operation of the main valve 70 since the camsurface 143 is held out of contact with the operating rod 86. Thus, acontinued cycling is prevented from occurring. This is normally to beavoided, since obviously a repeated stapling operation over the samespot would be undesirable. However, it is contemplated that underappropriate -circumstances where either the stapling machine is moved orthe workpiece is moved, the vertical sear 144 may be removed so that acontinued operation of the trigger would return the cam surface 143 tothe bottom of the operating member and cause a repeated cyclingoperation of the air motor.

Where it is desired to adjust the limits of eiective stroke of thedriving blade 60, the drive block control screw 69 may be adjustedtoward or away from the block. This will reduce the distance between thehead of the screw and the dog 142, or increase the distance and,accordingly, the length of stroke, depending on whether the screw isscrewed into or out of the block.

Where it is desired to vary the degree of penetration of the rotaryanvils into the material being worked upon,

the penetration control nut 45 may be operated. First the lock nut 47 isloosened. Then, since the nut 45 has a right hand thread, a clockwisemovement Of the nut will cause the chassis 41) to be elevated on thetrack or guides 31 relative to the base or frame 21. This Will raise thehandle and power mechanism of the stapling mechanism above the base ofthe machine. Consequent- 1y, the penetration of the anvils below thebottom of the base will be lessened. Conversely, a greater penetrationcan be efectuated by a counterclockwise movement of the nut 45, Thepenetration bar allows relative movement of the housing 40 with respectto it by virtue of the slots 42 in the housing through which the controlbar passes at its ends adjacent its connection to the base.

yIn the modification of FIG. 13, there is shown the air motor generallyindicated at 200 in which the valve housing 201 may be situated entirelyexteriorly of the cylinder 202. This permits easy maintenance andreplacement of parts, as well as providing for a simplifiedconstruction. In this embodiment of the invention, the main valve 209 iskept in the normally unope'rated position shown in FIG. 13 by thebiasing action of spring 234 and the application of pressure against theinside of valve 231. This seats the valve member 23@ against its valveseat 216 and opens valve member 231 with respect to its valve seat2.11.v The main Valve then allows high pressure from the inlet 205A tobe passed by port 213 into the bottom of the cylinder 202 underneath thepiston 203. Under this condition, high pressure air likewise flows pastthe valve member 231 to the passage 214 te be admitted to the bottom ofthe piston 242 in piston chamber 215. Pressure therein causes the upwardseating of the valve 208 so that its valve member 241 is seated againstits valve seat 220. This opens the valve member 240 with respect to itsValve seat 221, which is in communication through the passage 223 withthe top of the piston. Therefore, since the valve 240 is open to theexhaust chamber 217, the top of the piston is exhausted through theexhaust port 218 and the piston is maintained in its upward positionshown in FIG. 13.

The air motor 200 is adapted to be operated by energization of thesolenoid 223. When this occurs the detent mechanism 245 is pulledupwardly by magnetic force, and with it the valve rod is also movedupwardly against the force of the spring 234. The detent force isgreater than the force of the spring 234. When the foregoing occurs, thevalve member 231 of the main Valve 209 is closed so that high pressureair no longer is admitted to the bottom of the piston 203 nor to thebottom of piston 242. Simultaneously, the valve member 216 is opened sothat both the bottom side of the power piston 203 and the valve piston242 are opened through the valve 230 into the exhaust chamber 217 andout exhaust port 218.

As this occurs, the combined force of the poppet valve spring 243 andthe high pressure through inlet 205 acting on the annular area of thevalve piston 242 pops open the poppet valve 208. This opens valve member241 to the oW of high pressure air into the passageway 222 and closesthe valve member 240 against its valve seat 221. Thus, high pressure airwill flow through passage 222 and upwardly in passage 223 to the top ofthe power pisto-n 203 and cause it to move downwardly.

As the piston 203 moves downwardly, it carries with it the standard 250until the adjustable contacting nut 249 contacts the freely pivoted arm248. When this occurs, the arm 248 is forced against the flange 247 onthe main valve rod and overrides the ball detent mechanism biasing forceso that the valve rod moves downwardly with respect to said detent balls246. Thus, the contacting nut 249 causes the valve rod to return thevalve 209 to its original position in which it is maintained by highpressure air' and the return spring 234. Continued energization of thesolenoid no longer effects the operation of the motor. The solenoid`must be deenergized to permit the recoupling of the detent mechanism245 with the valve rod,

12 after which the above described operation may be repeated.

Either one of the described modifications of the air motors 150 and 200may be utilized with the stapling machine 20 or any other type ofstapling machine. It is further apparent that either one of these airmotors or air motor 23 may be used in other applications where a singlecycle motor is desired. These motors are of particular advantage whereit is desired to have a complete reciprocating cycle of a pistonoperating member which is 'effectuated by only a single control force.Thus, the control force need only be initiated and its reversal is notneeded to complete the cycle. This feature is of great advantage in manyoperations, as will be apparent to those skilled in the art, since thecontrol force need not be gauged or timed for successful consummation ofthe cycling operation.

Various changes and modifications of this invention may lbe made inaddition to those above described, as will be apparent to those skilledin the art. Such changes and modifications will Abe within the teachingsof this invention, as defined by the scope of therclaims appendedhereto.

What is claimed is: y

1. In ya'staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement comprising a fluid operated motorfor driving the piston rod connected with said driving blade means,including a trigger cooperating with a valve for actuating said motorand moving said piston rod through a staple driving operation, motorreversing means adapted to cooperate with said piston rod at the end ofthe staple driving cycle to reverse the `direction of operation of saidpiston rod and return the driving blade to complete a full cycle, saidlast named means including a cam connected with said trigger, and havingmeans cooperating with said piston rod at the end of the blade drivingoperation to reverse the direction of said piston rod.

2. In a staple machine having a piston, a piston rod and a connectedstaple driving blade, the improvement comprising a fluid operated motorfor driving the piston rod connected with said driving blade, said motorhaving a main valve movable between first and second limiting positions,a poppet valve movable between third and fourth limiting positionsresponsive to changes in fluid pressure determined by the position ofsaid main valve, trigger means for moving said main valve from said rstposition to said second position to actuate said motor through a stapledriving operation, and means operatively associated with said piston rodfor completing the cycle of said driving blade by returning itindependently of continued actuation of Vsaid trigger.

3. In a staple machine having a staple driving element, a fluid motorfor driving the element, valve mechanism for controlling the motor, saidvalve mechanism having manually movable means to operate the motor in adriving direction to drive the element and said valve mechanism lbeingreturnable to reverse the motor to return the element to startingposition, yieldable connections between the manually movable means andvalve mechanism, means operated by the motor upon movement to drivingposition to overcome the yieldable connections and return the valvemechanism, despite retention of the movable means in itsvalve-displacing position.

4. In a staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement comprising a fluid operated motorfor driving the piston rod connected with said driving blade, said motorhaving a main valve movable between first and second limiting positions,a poppet valve movable between third and fourth limiting positionsresponsive to the position of said main valve, trigger means for movingsaid main valve from said first position to said second position toactuate said motor through a staple driving operation, means operativelyassociated with said piston rod for completing the cycle of said drivingblade by returning it independently of continued actuation of saidtrigger, said last named means being adapted to cooperate with saidpiston rod at the end of the staple driving operation and return saidmain valve to the iirst position independently of continued operation ofsaid trigger, said means further including a cam having means thereonfor moving said main valve to its second position when the trigger isdepressed, and means for disengaging the trigger action independently ofcontinued operation through disengagement of the cam with said mainvalve for returning said main valve to its first position.

5. In a staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement comprising a uid operated motorfor driving the piston rod connected with said driving blade, triggermeans iucluding a trigger for actuating said motor through a stapledriving operation, means operatively associated with said piston rod forcompleting the cycle of said driving blade by returning it independentlyof continued actuation of said trigger, and means for varying thedistance of the stroke through which said piston rod operates.

6. In a staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement comprising a fluid operated motorvfor driving the piston rod connected with the driving blade, motoractuating means for actuating said motor and piston rod through a stapledriving operation, and motor reversing means adapted to cooperate Withsaid piston rod at the end of the staple driving cycle to reverse thedirection of operation of said piston rod and return the driving bladeto complete a full cycle, said last named means including biased detentmeans in said motor actuating means cooperating with said piston rod atthe end of the blade driving operation to disengage the motor actuatingmeans and return the piston rod to its original position.

7. In a staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement comprising a fluid operated motorfor driving the piston rod connected with the driving blade, motoractuating means for actuating said motor, said motor having a main valvemovable between first and second limiting positions, a poppet valvemovable between third and fourth limiting positions responsive to theposition of said main valve, said motor actuating means being adapted tomove said main valve from said first position to said second position toactuate said motor throught a staple driving operation, and meansoperatively associated with said piston rod for completing the cycle ofsaid driving blade by returning it independently of continued actuationof said trigger, said last named means being adapted to cooperate withsaid piston rod at the end of the staple driving operation and returnsaid main valve to the first position independently of continuedoperation of said motor actuating means, and including a piston adaptedto operate said main valve to its first position.

8. In a staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement comprising a uid operated motorfor driving the piston rod connected with the driving blade, motoractuating means for actuating said motor and piston rod through a stapledriving operation, motor reversing means adapted to cooperate with saidpiston rod at the end of the staple driving cycle to reverse thedirection of operation of said piston rod and return the driving bladeto complete a full cycle, said last named means including biased detentmeans in said motor actuating means operatively cooperating with saidpiston rod at the end of the blade driving operation to disengage themotor actuating means and return the piston rod to its originalposition, said motor actuating means further including a solenoid whichis adapted to attract said detent means upwardly, and an operating rodbiasedly held by said detent means.

9. In a staple machine having a piston, piston rod and a connectedstaple driving blade, the improvement das comprising a fiuid operatedmotor for driving the piston rod connected with the driving blade, motoractuating means for actuating said motor, said motor havinga main valvemovable between first and second limiting positions, a poppet valvemovable between third and fourth limiting positions responsive to theposition of said main valve, said motor actuating means being adapted tomove said main valve from said first position to said second position toactuate said motor through a staple driving operation, means operativelyassociated with said piston rod for completing the cycle of said drivingblade by returning it independently of continued actuation of saidtrigger, said last named means being adapted to cooperate with saidpiston rod at the end of the staple driving operation and return saidmain valve to the first position independently of continued operation ofsaid motor actuating means, said motor actuating means further includinga solenoid which is adapted to attract said detent means upwardly, andan operating rod biasedly held by said detent means, and said motorreversing means including a movable contact element carried by saidpiston rod, which element is adapted to contact said operating rod atthe end of the staple driving operation lto return said main valveagainst the force of the detent and said solenoid to its first position.

10. A uid operated motor having a piston rod and a piston, said motorhaving trigger means including a trigger for actuating said motor andpiston rod through a driving operation, motor reversing means adapted tocooperate With said piston rod at the end of the driving cycle toreverse the direction of operation of said piston rod and return themotor to complete a full cycle, said last named means including a camoperatively associated with said trigger, and said cam having meanscooperating with said piston rod at the end of the driving operation toreverse the direction of said piston rod.

l1. A fluid operated motor having a piston rod and a piston, said motorhaving a main valve movable between first and second limiting positions,a poppet valve movable between third and fourth limiting positionsresponsive to changes in uid pressure determined by the position of saidmain valve, trigger means for moving said main valve from said firstVposition to said second position to actuate said motor through a drivingoperation, means operatively associated with said piston rod forcompleting the cycle of said driving operation by returning itindependently of continued actuation of said trigger, said last namedmeans being adapted to cooperate with said piston rod at the end of thedriving operation and return said main valve to the first positionindependently of continued operation of said trigger, said means furtherincluding a cam having means thereon for moving said main valve to itssecond position when the trigger is depressed, and means for disengagingthe trigger action independently of continued operation for returningsaid main valve to its lirst position.

12. A uid operated motor having a piston rod and a piston, said motorhaving trigger means including a trigger for actuating said motorthrough a driving operation, means operatively associated with saidpiston rod for completing the cycle of said driving operation byreturning said piston rod at the end of its drawing stroke independentlyof continued actuation of said trigger, and means for varying thedistance of the stroke through which said piston rod operates.

13. A uid operated motor having a piston rod and a piston, said motorhaving means for actuating said motor and piston rod through a drivingoperation, and motor reversing means adapted to cooperate with saidpiston rod at the end of the driving cycle to reverse the direction ofoperation of said piston rod to complete a full cycle, said last namedmeans including biased detent means in said motor actuating meansoperatively cooperating with said piston rod at the end of the drivingoperation to disengage the motor actuating means and return the pistonrod to its original position.

14. A iiuid operated motor having a piston rod and a piston, said motorhaving means for actuating said motor and piston rod through a drivingoperation, motor reversing means adapted to cooperate with said pistonrod at the end of the driving cycle to reverse the direction ofoperation of said piston rod and return the piston rod to complete afull cycle, said last named means including biased detent means in saidmotor actuating means cooperating with said piston rod at the end of thedriving operation to disengage the motor actuating means and return thepiston rod to its original position, said motor actuating means furtherincluding a solenoid which is adapted to attract said detent meansupwardly, and an operating rod biasedly held by said detent means.

15. A iiuid operated motor having a piston rod and a piston foractuating said motor, said motor having a main valve movable between rstand second limiting positions, a poppet valve movable between third andfourth limiting positions responsive to the position of said main valve,said motor actuating means being adapted to move said main valve fromsaid rst position to said second position to actuate said motor througha driving operation, means operatively associated with said piston rodfor completing the cycle of said power means by returning itindependently of continuedV actuation of said trigger, saidV last namedmeans being adapted to cooperate with said piston rod at the end of thedriving operation and return said main valve to the first positionindependently of continued operation of said motor actuating means, saidmotor actuatingV means further including a solenoid which is adapted toattract said detent means upwardly, and an operating rod biasedly heldby said detent means, and said motor reversing means including a movablecontact element carried by said piston rod, which element is adapted tocontact said operating rod at'the end of the driving operation to returnsaid main valve against the force of the detent and said solenoid to itsfirst position.

16. In a machine of the kind described: a cylinder and a pistonreciprocable between first and second ends of the cylinder; a valvedevice having a dual valve movable to a iirst position wherein itconnects the second end of the cylinder to a high pressure fluidpassage, and movable to a'second position wherein it connects the secondend of the cylinder to exhaust; means to move the valve, including ayieldable means urging it toward its iirst position to port highpressure fluid, and a uid pressureresponsive wall connected to the valveto move it to its second position to port the second end of the cylindertoV exhaust; the pressure-responsive wall being subjected to iiuidpressures corresponding to those in the first end of the cylinder, theyieldable means having a force to displace the valve Vagainst exhaustpressures on the wall, but yieldable to pressures on the wallcorresponding to piston-moving pressures in the iirst end of thecylinder; and means to connect the irst end of the cylinder to the highpressure fluid passage and to exhaust.

17. In a iluid motor: a cylinder, a piston reciprocable Vin thecylinder; and valve mechanism for controlling admission and emaust ofiiuid lto the opposite ends of the cylinder, the mechanism including amain valve and a secondary valve; lthe main Valve being oppositelymovable to a first position wherein it ports one end of the cylinder toa high pressure inlet, and to a second position wherein it ports theIsame one end of the cylinder to exhaust; the secondary valve being alsooppositely movable to -a first position wherein it ports the other endof the cylinder to exhaust, and to a second position wherein it portsthe said other end of the cylinder to the high ypressure inlet; means tomove the secondary valve from its second position -to its firstposition, including a iuid pressure-responsive device connected tooperate the valve, and having passage means connected to subject it tofluid pressure conditions corresponding to those in the said one end ofthe cylinder so that when the fluid pressure conditions in the said oneend of the cylinder are high, the valve will be moved to its iirstposition; and yieldable means to urge the secondary valve into itssecond position when fluid pressure conditions in the said one end ofthe cylinder are low.

18. The fluid motor of claim 17, wherein the main valve has yieldablemeans normally urging it into its rst position; and means to displace itto its second position.

19. The fluid motor of claim 18, wherein the last- Vnamed displacingmeans includes a device displaceable to move the main valve into itssecond position, said device having a relasable connection with thevalve; and means operable by the piston as it reaches its secondposition to cause release of the connection and return of the main valveto its rst position under action of the yieldable means.

20. The motor of claim 19, wherein the displaceable device includes atrigger, a cam movable by the trigger and adapted to engage the mainvalve -to displace it, the releasable connection comprisinga movablemounting ,for the cam whereby it may move relatively to the trigger,

away from the valve; and the means operable by the piston lincluding apart on the piston engageable with a part on the cam to move the latteraway from the valve.

2l. The motor of claim 18, wherein the displacing means comprises a.power device, a releasable connection between the power device and themain valve, the connection providing for movement of lthe valve uponoperation of the power device, but being releasable to enable the valveto be moved independently from the power device.

22. The mechanism of claim 20, wherein the cylinder includes twocylinder heads and a cylindrical element between them; one of thecylinder Vheads having two cylindrical passages therein, and the twovalves being reciprocably mounted for valving movements in thecylindrical passages.

23. The mechanism of claim 19', wherein there is a base and a chassis;the cylinder, piston and valves being securely mounted on the chassis;and a handle also securely mounted on the chassis, the devicedisplaceable to move the main valve comprising a trigger mounted on thehandle so that the piston may-be caused to operate by a user holding themachine by the handle and operating the trigger.

24. The mechanism of claim 23 wherein the chassis is adjustably mountedon the base so that the end position of operation of the piston,relatively to the base, is adjustable.

25. The mechanism of claim 23, wherein there are driving means connectedto the piston for driving objects supported on the base to positionsdetermined by the extreme position of .the piston relatively to thebase, and means to adjust the position of the chassis relatively to thebase, to thereby adjust the extreme driven position of the piston, andof the object driven thereby.

26. The combination of claim 25, wherein the base includes pantsengageable ito rest upon a surface, and upright parts, the chassisincluding a chassis part mounted slidablfy upon the upright parts of thebase; displacement means interengageable between the base and chassismovaible to displace the chassis slidably on the base, and means tosecure the chassis against further such movement.

27. The combination of claim 23, wherein the base includes an elongatedhorizontal portion engageable -to rest upon a surface, and upright partsat one end thereof, the chassis being attached to the upright parts, andthe handle extending back over the horizontal portion of the base, andthe cylinder being mounted with its piston rod movable between theupright parts of the base and the handle.

28. In a machine of the kind described, a base having a Work-engagingsurface, a chassis, a cylinder yand piston therein, Valve means forcontrolling operation of the piston, mechanism to operate the valvemeans, and a handle, the chassis, cylinder, valve means, the mechanismto operate the valve means, and handle all being connected together intoa subassembly that is adjustably mounted on the base; and means toadjust the subassembly on the base ltoward and from the Work-engagingsurface.

29. 'I'he machine of claim 28, wherein the piston moves toward and fromthe Work-engaging surface and has a piston rod and article-driving meansconnected to it, and means on lthe base to hold articles tobe disposedin the path of the driving means.

30. The combination of claim 28, wherein the piston has article-drivingmeans and article-receiving means connected to it to be driven by pistonmovement toward the work-engaging surface; the base having upright partsextending perpendicularly to the Work-engaging surface, upon which vthechassis is mounted, the article-driving and article-receiving meansbeing mounted behind the chassis, and the handle projecting generallyparallel to the Workengagng surface beyond Lthe articledriving means,and spaced from the base.

References Cited in the le of this patent UNITED STATES PATENTS CurtisMay 18, Curtis May 18, Burger Apr. 8, Hanna May 9, Emst Sept. 19,Boynton July 24, Muir June 17, Shaft Aug. 1, Larson Dec. 23, SchairothMay 3, Mothorn Nov. 15, Schafroth Nov. 22, Van Sittert May 8, WandelJune 26, Fischer Nov. 6, Lang Nov. 6, Iuilfs Feb. 19, Dupre Aug. 18,Aldrich May 3, Schafroth et a1. Nov. 1, Faccou Ian. 3, Schafroth Nov.20, Faccou Ian. 7,

UNITED STATES PATENT OFFICE CERTIFICATE 0F CORRECTION Patent No.,2,989,948 June 2L, 1961 William A. Forrester It is hereby certified thaterror appears injbhel above numbered patent requiring correction andthat the said Letters"L Patent should read as 'corrected below Column2,: line 42, for "'anvile" read anvil column 3, line 18, after "trgger;"insert and --g line 58, for "it," read its column 6, line 10, after"its" insert main column 9, line 48 for "surfaced" read surface --gcolumn 13, line 47, for "throught" read JEhrough column 16, line 15, for"relasable" read releasable.

Signed and sealed this 28th day of November 1961.

' (SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer i Commissioner ofPatents USCOMM-DC-

